During a scientific expedition in Iceland, visionary scientist Trevor Anderson (Brendan Fraser), his nephew Sean (Josh Hutcherson) and their beautiful local guide, Hannah (Anita Briem), are unexpectedly trapped in a cave from which their only escape is to go deeper and deeper into the depths of the Earth. Traveling through never-before-seen worlds, the trio comes face-to-face with surreal and unimaginable creatures--including man-eating plants, giant flying piranha, glow birds and terrifying dinosaurs from days past. The adventurers soon realize that as volcanic activity increases around them, they must find a way back to the Earth's surface before it is too late.